1. Field of the Invention
This invention relates to apparatus for circulating water within a large body of water. Specifically, it relates to apparatus which amplifies the flow of a pump which ordinarily operates efficiently at a high head of water, enabling the pump to operate at a low head of water at high efficiency.
2. Background Discussion
In sewage treatment, fish farming, and other industrial applications, it is necessary to aerate and circulate a body of water. The reason is to introduce sufficient quantities of oxygen into the water so that it will not become stagnant. Depending upon the size of the body of water, different types of pumps are employed to circulate water, moving water from the lower regions to the surface. In general, however, the pumps commonly employed are designed to operate at a high head of water. In other words, in order for the pump to operate efficiently, the load on the pump must be high. For example, typically a 5 horsepower (HP) pump of conventional design will require a head of 25 feet of water in order to operate at an efficiency of 60%. Pumps used for these applications are not designed to operate at low loads or low heads of water.
In many applications, aeration can be accomplished by simply circulating the body of water, taking the water from the lower depths and moving this water to the surface. Such circulation does not require a high or large head. Typically, if the water is pumped from six inches to two feet above the surface of the water, this is sufficient to accomplish the desired circulation. The problem is that this cannot be accomplished efficiently using conventional pumps. The inefficient operation of the pump results in the waste of large quantities of electrical energy. This contributes substantially to the cost of aeration and, in many instances, makes it economically unfeasible to aerate certain bodies of water using conventional pumps.